This invention relates to an improved process for inlaying a design in molded simulated marble, hereinafter called, "cultured marble", or marble.
In general, cultured marble, commonly used for sinks, vanity tops, etc., is molded in a mold, which may be in the form of a shallow tray or pan, by applying a transparent release coating (of wax, for example) to the inside of the tray, applying a gel coating on the release coating, allowing the gel coat to gel, and pouring a marble mix in the mold on the gel coat. What is herein called "marble mix" generally comprises a synthetic resin material, catalyst, filler and pigment, the latter being blended into the marble mix to give the finished "marble" the desired color pattern. After the marble mix has hardened into "cultured" marble, the slab with the transparent gel coat thereon is removed from the mold.
Inlaying design in cultured marble does not appear to have been practiced in modern times, although there is some disclosure in U.S. Pat. No. 125,122, issued Apr. 2, 1872, of embedding ornamental objects in artificial marble. The process disclosed in that patent involves laying an object of metal, wood, glass or other rigid material on a mold surface, filling the mold with marble mix, allowing the mix to harden, and then removing the resultant marble slab with the object embedded therein from the mold. However, the marble slab was in an unfinished state and required considerable finishing to give it the desired surface characteristics. Thus, the patentee discloses that "when the marbles or embedded designs are removed from the molds or surfaces on which they are formed, they are rubbed down and stopped with cement. Where any holes may occur they may then be stoned with cement and allowed to dry, after which they are ready for polishing or enameling by the usual processes . . . . " This process clearly was quite time-consuming and required a great deal of handwork.
Similarly, U.S. Pat. No. 4,209,486, issued to Ross, describes a method whereby porous flexible sheet material bearing a design is affixed to the gel coat and then covered with hardenable marble mix.
However, nowhere in the prior art is there taught a process which can withstand substantial thermal and mechanical stress over a prolonged period of time.